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Windows 7 x64 Host - VT-x not recognized

Posted: 12. Nov 2009, 04:20
by WhiteZero
I'm running a Windows 7 Ultimate x64 host with an Intel E8400 processor. I've double checked to make sure Virtualization Tech is enabled in BIOS. However, VirutalBox does not recognize that I have the feature now that I'm on Windows 7. I've used VirtualBox in Vista x64 with no problems on the same hardware, I could run x64 Guests with no issue.

I've reinstalled my chipset software as well. VirtualBox still refuses to recognize my VT-x hardware acceleration.

I'm using the latest VirtualBox, 3.0.10 r54097

This might be a problem with Windows 7 because VMWare won't let me run 64bit hosts either. Any recommendations?

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 12. Nov 2009, 20:30
by rasta
On a 64-bit Windows hosts with processors that support VT-x, does VT-x support need to be enabled in the BIOS?

I am running Vbox on a 32-bit WinXP host now, and VT-x support is enabled in the BIOS. I am about to install WinXP x64 on it. Should I turn VT-x support off when I do so, or leave it on?

I want to run 64-bit Solaris guests.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 12. Nov 2009, 20:53
by vbox4me2
Reboot the Host and go into the BIOS
disable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
start the Host and go into the BIOS
enable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
Boot the Host.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 12. Nov 2009, 21:27
by WhiteZero
vbox4me2 wrote:Reboot the Host and go into the BIOS
disable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
start the Host and go into the BIOS
enable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
Boot the Host.
Wow, that actually worked! Thank you, vbox4me2!

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 19. Jan 2012, 11:14
by Tomo59
Yes, it actually worked for me too !

Thanks vbox4me2

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 12. Mar 2012, 00:48
by LucasAU
To echo the "me too"'s ... me too. Pulling power for 10 seconds did the trick on a Dell Optiplex 960.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 12. Mar 2012, 10:53
by mpack
Those with the "Me Too's" might wish to be explicit about which PC/laptop they are referring to, because it seems clear to me that this "fix" can only be a workaround for a BIOS bug, i.e. flash config changes not being reflected in a RAM copy. Alternatiely, perhaps this happens because the user made BIOS changes but has not reboot the host since (always hibernates). I would like to know if the above rigmarole is actually needed - or would a simply full shutdown (not hibernate) and restart be enough.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 14. Mar 2012, 05:02
by zeke009
Quick note for those using an X79 Chipset:

In the UEFI BIOS, version F9 on the Gigabyte GZ-X79-UD3 you have to enable both Virtualization and VT-d. Once those are enabled VirtualBox works fine, enabling just Virtualization will result in an error.

This is found on the BIOS Features tab.
GA-X79-UD3 - Virtualization2.png
GA-X79-UD3 - Virtualization2.png (22.58 KiB) Viewed 29180 times
One other note: Using the Windows based tool to edit UEFI options resulted in corruption for me and required clearing CMOS to resolve. I'm not a fan, so just a heads up on that little gem.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 14. Mar 2012, 10:42
by michaln
zeke009 wrote:enabling just Virtualization will result in an error.
What error?

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 15. Mar 2012, 04:29
by zeke009
michaln wrote:
zeke009 wrote:enabling just Virtualization will result in an error.
What error?
Sorry, I should have grabbed a screenshot. It says Virtualization is available, but not functional. I'll try to recreate the error when I have some time this week.

Re: Windows 7 x64 Host - VT-x not recognized

Posted: 17. Mar 2012, 15:58
by zeke009
I reset my BIOS to the conditions that this happened in last time and the VM did not through the error. When I had the problem then VM I was using was brand new, I'm not sure if that was part of the problem or not. However, on an X79 Chipset I'd recommend enabling VT options if you get an error about "is present, but not functional".